84 lines
2.7 KiB
Python
84 lines
2.7 KiB
Python
# Адресный PING SETProtocol v2 через сегментированный classic CAN. Ответ сопоставляется с
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# ожидаемым обменом; успешная отправка CAN-пакета ещё не подтверждает доступность прикладного
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# сервиса.
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"""Addressed SETProtocol v2 PING exchange over segmented classic CAN."""
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from __future__ import annotations
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from dataclasses import dataclass
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from time import perf_counter
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from setprotocol.can import CanAddress, CanFrame, CanReassembler, segment
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from setprotocol.core import (
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Frame as SetFrame,
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FrameFlag,
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MessageType,
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SetProtocolError,
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Status,
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build_frame,
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decode_datagram,
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decode_response,
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)
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from . import can_transport as tr
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@dataclass(frozen=True)
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class CanPingReply:
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node_id: int
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uptime_ms: int
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protocol_version: int = 2
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class CanPingExchange:
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def __init__(self, node_id: int, sequence: int = 1, channel: int = 1) -> None:
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if not 0 <= node_id <= 0xFF:
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raise ValueError("SETP node ID вне диапазона 0..255")
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self.node_id = node_id
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self.sequence = sequence & 0xFFFF or 1
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self.channel = channel
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self._reassembler = CanReassembler()
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def request(self) -> list[tr.Frame]:
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packet = build_frame(
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SetFrame(
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MessageType.PING,
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self.sequence,
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flags=FrameFlag.ACK_REQUIRED | FrameFlag.PRIORITY,
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source=0,
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destination=self.node_id,
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)
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)
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return [
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tr.build_frame(item.can_id, item.data, to_can=True)
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for item in segment(packet, CanAddress(self.node_id, 0, 1, self.channel))
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]
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def feed(self, frame: tr.Frame) -> CanPingReply | None:
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if frame.to_can or not frame.ide:
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return None
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try:
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address = CanAddress.unpack(frame.can_id)
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if address.source != self.node_id or address.destination != 0:
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return None
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packet = self._reassembler.feed(
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CanFrame(frame.can_id, frame.data), int(perf_counter() * 1000)
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)
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if packet is None:
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return None
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response = decode_datagram(packet)
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status, body = decode_response(response)
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except SetProtocolError:
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return None
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if (
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response.message_type != MessageType.PING
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or response.sequence != self.sequence
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or response.source != self.node_id
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or response.destination != 0
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or status != Status.OK
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or len(body) != 4
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):
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return None
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return CanPingReply(self.node_id, int.from_bytes(body, "little"))
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